Evidence Hub

Intratrial Exposure to Vitamin D and New-Onset Diabetes Among Adults With Prediabetes: A Secondary Analysis From the Vitamin D and Type 2 Diabetes (D2d) Study. Diabetes Care 2020;43:2916–2922

M. Davidson

Diabetes Care, 2020

37 citations

Abstract

This letter concerns the secondary analysis (1) of the Vitamin D and Type 2 Diabetes (D2d) study (2). The D2d study was a randomized controlled trial to determine whether vitamin D supplementation (4,000 IU per day) reduced the risk of diabetes among adults with prediabetes (2). In an intention-to-treat analysis, vitamin D nonsignificantly reduced new-onset diabetes by 12% compared with the placebo (2). A secondary analysis was subsequently performed that evaluated hazard ratios (HRs) of developing diabetes in the entire cohort stratified by different achieved levels of vitamin D (1). When adjusted for treatment assignment only (vitamin D or placebo [model 1]) and compared with the cohort of achieving the vitamin D sufficient range of 50–75 nmol/L, those in the highest two cohorts of achieved vitamin D levels of 100–124 nmol/L and $125 nmol/L had significantly decreased HRs of 0.65 and 0.41, respectively (1). The results were progressively adjusted for the following potential confounders: baseline BMI, race (model 2); sex, age (model 3); baseline physical activity (model 4); and baseline statin use (model 5). All of these adjustments lowered the HRs of model 1 of the 100–124 nmol/L and $125 nmol/L cohorts by only 0.08 and 0.06, respectively, suggesting that these potential confounders did not play a large role. Weight loss is the most important factor in delaying or preventing the development of diabetes in individuals with prediabetes (3). It seems possible that those…

How strong is the evidence?

Evidence Hub reads this as a secondary / pooled analysis, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free